Collagen casing



J. T. MCKNIGHT COLLAGEN CASING Oct. 6, 1964 2 Sheets-Sheet 1 Filed June5, 1961 TILC'J.

72/15/011 2 ounds INVENTOR J/wss 7T Mam/ n- I Oct. 6, 1964 Filed June 5,1961 2 Sheets-Sheet 2 Lo l l 05 I I I o" I I I 72/15/00 /)7 ounds l2 l-lUnited States Patent Ofiice Patented Get. 6, 1964 3,1519% (IQLLAGENCASl'NS Flames T. McKnig t, Somerville, NJ, assignor to Zlohnson 8;Johnson, a corporation of New Jersey Filed dune 5, 1961, Ser. No.114,823 12 Claims. Cl. 99l76) This invention relates to an improvedcollagen casing and more particularly to extruded collagen casingsderived from a fluid mass of swollen collagen fibrils.

\Vhile not limited thereto, the present invention is adapted to beingutilized as a casing for sausages of the Wiener or frankfurther type.Prior to the present i vention, this type of sausage was either preparedby using expensive natural casings or unedible cellulose casings tocontain the meat emulsion during the smoking and cooking process. Theunedible cellulose casing must be removed by the manufacturer before thewieners are packaged for sale. The resulting product is known in themeat industry as a skinless Wiener.

There has long been a need for an extruded collagen casing that would beedible, non-toxic and sufficiently strong to stand up under sturling,linking, smoking, washing and cooking. It is now known that ediblecasings for pork sausage may be prepared by extruding a tubular bodyfrom a iluid mass of swollen collagen fibrils, hardening this tubularbody in the wet state and drying the collagen casing so produced. Amethod of producing such collagen casings is described and claimed incpending application Serial No. 82,934, filed January 16, 1961.

Extruded collagen casings that are suitable for the manufacture of freshpork sausages may not be entirely satisfactory for the production ofsausages of the Wiener or frankfurter type. This is due to thedifferences in processing pork sausages and wieners. Thus, a meatemulsion of the pork sausage type may be stuffed, linked by twisting ona FAMCO linking machine, and packaged for sale without cooking. Sausagesof the Wiener 0r frankfurter tvce, however, are linked on a Ty linker,racked on a stick, smoked at temperatures from about 120 F. to about 170or 180 F. for several hours, rinsed with hot water at about 180 to 190F. for several nunutes, and then rinsed with cold water for severalminutes. It will be appreciat d, therefore, that a collagen casing usedin the production of irankfurters must of necessity be tougher and havea high wet strength to survive the treatment in the Ty linker.

An additional requirement for the frankfurter casing is that the casingshould not become wrinkled and lose bonding to the meat during smokingor the hot and cold rinses that follow smoking. In other words, thecasing must be sufficiently elastic (not permanently deformed) so thatthe stress does not relax during the smoking-rinsing cycle. On chillingafter smoking, the meat contracts sligatly (becomes more dense) and thecasing must also shrink or the finished product will have a poorappearance.

it is an obiect of the present invention, therefore, to produce a newand improved extruded collagen casing adapted to be utilized as a casingfor sausages of the Wiener or frankfurter type.

it is another object of the present invention to produce an edible,non-toxic casing that will survive linking in the Ty linker.

it is a further object of this invention to produce an edible collagencasing that will retain a smooth symmetrical appearance after smoking.

Still another object of tms invention is to provide an edible collagenfrankfurter casing that will not peel oil, even when punctured duringcooking.

In accordance with the present invention, it has been discovered that asuitable Wiener casing may be produced by extruding a fluid mass ofswollen collagen fibrils in the form of a tubular body into acoagulating liquid and hardening the tubular body while it is in the wetstate. The collagen tube so obtained is washed with water and thentreated with a very dilute solution of a reducing sugar. Finally, thesugar-treated casing is dried and then heat-cured by heating for about16 to 24 hours to a temperature of about C.

While I do not wish to limit the present invention by particular theory,it seems probable that the small amount of reducing sugar that is addedto the collagen in its wet state is absorbed and during the heat-curingcycle effects a chemical bonding, thereby producing a casing with agreater wet tensile strength and toughness, a tighter, less deformablenetwork structure, an increased tendency to shrink during cooking, andan increased tensile strength after cooking. Regardless of the mechanismof the reaction, the improvement in physical properties described abovecan be obtained by adding a very small amount of a reducing sugar to thecasing prior to the drying step.

it must be emphasized that increasing the amount of sugar and changingthe heat-treatment conditions will prouce an unacceptable product thatWill shrink too much on cooking. At low sugar concentrations, of theorder of 0.005 percent to about 0.20 percent, the increased shrinkage oncooking is so small as to be acceptable with many pork sausages. Thus,by the novel procedure of the present invention, using edible chemicals,a universal casing may be obtained in that the casing may be used for Tylinked pork sausage, for Farnco linked pork sausage and as a Wiener orfrankrurter casing.

Suitable sugars for the treatment of collagen casings are reducingsugars which have a free aldehyde or keto group that is not in glucosidecombination with other molecules. Examples of such reducing sugars areerythrose, threose, arabinose, ribose, xylose, cyclose, fucose, mannose,glucose (dextrose), galactose, fiuctose (levulose), etc. These sugarsmay be most conveniently applied to the collagen casing in the form ofdilute solutions. The amount of sugar present in solution is related tothe dwell time of the casing in the solution and the reactivity of thesugar used. Thus, a reactive sugar such as galactose may be used atconcentrations as low as 0.005%. If the amount of galactose exceeds0.2%, the sugar curing will proceed too far and result in a brittlecasing that can not withstand the stress of Ty linking. A less reactivesugar such as mannose will not produce the required wet tensile strengthunless the concentration of reducing sugar is greater than 0.005percent. It is preferred to add the reducing sugar to the plasticizingbath, which bath follows the washing step and is the last bath contactedbefore the casing is dried.

The amount of sugar employed in the treating bath is also dependent uponthe time and temperature of heat treatment. The sugar-treated casing maybe dried and heat-cured at a temperature of about 80 C. Heating thecasing above about C. for too long a period degrades the collagen andresults in a somewhat brittle casing that breaks when the links aretied. At temperatures appreciably below 70 C., the time required forheat-curing is so long as to be impractical. The preferred method ofheat-curing a sugar-treated collagen casing is to dry the casing afterit leaves the sugar solution, shirr the casing and then heat the Shirredcasing in a forced draft oven by raising the temperature slowly from 35C. to 80 C. during 8 hours. The casing is then heated at 80 C. for anadditional 16 hours to complete the curing operation.

It will be understood that the foregoing general description and thefollowing detailed description, as well, are exemplary and explanatorybut they do not restrict the invention.

The process for the manufacture of sugar-cured collagen casings of thepresent invention may be more fully understood from the followingdetailed description and examples taken in connection with theaccompanying drawings, wherein:

FIGURE 1 is a reproduction of a stress-strain curve of a typicalcollagen casing of the present invention obtained from an InstronTensile Tester machine.

FIGURES 2 and 3 are similar stress-strain curves but differ from FIGURE1 in the size and temperature of the casing sample tested.

Throughout the specification and examples that follow, all quantitiesare expressed in parts by weight unless otherwise indicated.

Example 1 Fresh steer hides are washed with cold Water at 60 C. or lessin a roating drum for to 24 hours. After washing, the hides aredefieshed with a scraping machine and the hair and epidermis are cut offwith a horizontal band knife. This preliminary cleaning is accomplishedwith standard tannery equipment.

The remaininghair and poorly cleaned sections are cut off by hand andcomposites prepared from five hides. The hide composites are then cutinto /2 to 4 square inch sections and reduced to pulp by three passesthrough a meat grinder, each pass being a finer grind. The first andsecond passes are through 18 and 8 millimeter holes respectively. Thefinal grind is through holes 1.5 millimeters in diameter. It isimportant during the grinding process to keep the pulp below 20 C. Thismay be done by adding crushed ice to the hides as they are fed to thegrinder.

The ground pulp is next diluted with tap water containing a dispersionof hardwood cellulose fibers to give a smooth slurry containing 4percent dry hide solids and 1 percent dry cellulose fibers. This slurry(200 parts) is then treated with 50 parts of a 6 percent lactic acidsolution using an inline mixer such as that manufactured byCherry-Burrell (Model 24) to form a homogeneous mass of swollen collagenfibrils, and cellulose fibers. It is important during this acid swellingstep that the temperature be maintained below about 25 C. The mixture soobtained contains 3.2 percent hide solids, 0.8 percent cellulose fibersand ,1.2 percent lactic acid. After the pulp is blended with acid, themass of swollen collagen fibrils and cellulose fibers is furtherdispersed in a suitable homogenizer fitted with a two-stage valve andoperated with a 1500 psi drop per stage. The swollen collagen mass soobtained is filtered through a 7-mil filter screen and extruded in theform of a tube in such a way that some collagen fibril orientation istransverse to the direction of extrusion. This may be partiallyaccomplished by inflating the casing as it leaves the nozzle. One formof extruder found useful inpracticing the invention is disclosed incopending application Serial No. 82,933, filed January 16, 19,61.

The extruded collagen tube of swollen collagen fibrils is coagulated for6 minutes in an aqueous ammonium sulfate bath containing 40 percentammonium sulfate adjusted to a pH of 7.0 with ammonium hydroxide and isthen prewashed with 15% ammonium sulfate similarly adjusted to pH 7.5for an equal period of time.

Alum tanning of this extruded casing is accomplished by treatment withan alum solution containing 3 percent alum [NI-l Al(SO -12H O], 0.65percent citric acid and 4.0 percent ammonium sulfate. The contact timeis 6 minutes and this alum tanning solution is maintained at a pH ofabout 4.3. After the tanning step, the casing is Washed in tap water for17 minutes using three changes of water. The casing is finallyplasticized by passing it through a bath containing 3.7 percent glyceroland 0.02 percent dextrose. The dwell time in this bath is 10 minutes.The casing is inflated and dried for 10 minutes in a rapid stream of airand then heabcured in a forced draft oven raising the temperature slowlyfrom 35 C. to C. during an 8 hour period. The heat treatment at 80? C.is continued for an additional 16 hours.

The casing made by the method described above is of uniform diameter andwall thickness. The casing wall is a smooth and continuous film about 1mil in thickness and dispersed throughout the wall of the casing may benoted the cellulose fibers that were added to the original cowhide pulpin preparing the collagen mass. The collagen fibrils that make up thecasing wall cohere to form a membrane having the glass-like quality of ahyaloid membrane, but unlike the hyaloid membrane which is transparent,the collagen membrane is translucent.

Typical casings made by the process described above are tested on anInstron Tensile Tester to determine certain physical properties. TheInstron Tensile Tester is a machine which can apply a tensile load to asample and simultaneously record on a moving chart the stress-straincurve of the sample under test. The Instron apparatus employed to obtainthe data reported below was adapted to the testing of extruded collagencasings by enclosing the clamps of the instrument in an insulated boxwhich could be filled with live steam to maintain the sample at 99 C.All casings tested at 99 C. are pretreated by soaking in a meat emulsionextract for three minutes. This extract is prepared in the followingmanner.

A mixture of 1 part by weight ground sausage meat and 2 parts by weightis mixed thoroughly in a Waring Blendor and the water extract isseparated from the meat by filtration. The meat emulsion extract soobtained is heated to the boiling point to coagulate certainwatersoluble proteins and then filtered a second time to give a clearyellow solution that is used to pretreat the casings that are to betested.

A 4-inch length of the casing which has been soaked for 3 minutes in themeat emulsion extract described above is clamped between the jaws of theInstron Tensile Tester in such a manner that the length of the casingsuspended between the two jaws is 3 inches. The jaws of the Instronapparatus are then positioned 1 inch apart and live steam is admitted tothe insulated box that surrounds the sample and jaws of the apparatus.The temperature of the casing sample being tested is maintained at 99 C.throughout the entire test procedure.

Three minutes after the steam is admitted to the insulated box thatsurrounds the casing sample being tested, the clamps of the InstronTensile Tester are moved apart at the rate of 1 inch per minute untilthe casing breaks. While the jaws of the apparatus are in motion, thestress or tension exerted by the casing and the distance between themoving jaws is continuously recorded by a moving stylus on graph paper.FIGURE 1 is a reproduction of a typical stress-strain curve from anInstron Tensile Tester chart. It will be noted that the displacementalong the ordinate corresponds to the distance separating the jaws ofthe machine in inches. The displacement along the abscissa correspondsto the load on the jaws or tension exerted by the casing in pounds.

Five important physical properties of the casing under test can bemeasured from a single stress-strain curve. It Will be noted from FIGURE1 that no tension is recorded until the clamps have moved 1.48 inchesapart. Thisdistance from the intersection of the X axis and the Y axis(no displacement) to point 10 is a measure of the length of the casingafter steaming for 3 minutes and the original length (3 inches) minusthe distance from the point of origin to point 10 is the change oflength due to shrinkage, which throughout this specification will bereferred to as AL. In FIGURE 1, AL is equal to 3 inches minus 1.48inches or 1.52 inches.

From the slope of the line 10-11 in FIGURE 1, it

will be noted that the strain in inches per pound of stress is 3.43.This value, which is related to the reciprocal of Youngs modulus, willbe referred to throughout the specification as s.

In FIGURE 1, point 12 indicates the sudden breaking point of the casing,the tension dropping suddenly to zero. The point 12 is a measure of thetension or applied force at the break point. The casing having thestress-strain curve illustrated in FIGURE 1 snapped under an appliedforce of 0.591 pound. The force required to break the casing under thetest conditions described above will be referred to throughout thisspecification as the hot tensile strength.

The stylus trace 12 of FIGURE 1 passes through the point 13, at whichpoint the distance between the clamps is equal to the original length ofthe casing suspended between the clamps (3 inches). The displacement ofthis point 13 from the Y axis is a measure of the tension exerted whenthe casing is stretched to its original length. This force, which in thetest illustrated by FIGURE 1 amounts to 0.461 pound, will be referred tothroughout this specification as the shrink tension.

The line 1244 of FIGURE 1 intersects the Y axis at 3.04 inches,indicating that the casing measured 3.04 inches in length just prior tobreaking. The length of the casing at the break point divided by theoriginal length of the casing suspended between the clamps andmultiplied by 100 (3.04 inches 3 inches X 100), will be referred tothroughout the present specification as the percent recovery. In Lhetest illustrated by FIGURE 1, the pe cent recovery of the casing is 101.

The Instron Tensile Tester may also be used to determine the swell,deformation, modulus and wet tensile strength of typical casings at roomtemperature. In this experiment, the casings tested are not treated withthe eat emulsion. Test samples of the casing are prepared by cutting2-inch sections, /2-inch wide, from the casing in such a manner that thelong direction of the test sample (2 inches) is parallel to the axis ofthe casing. Other samples are prepared by cutting the 2-inch section insuch a manner that the long dirnension of the test sample isperpendicular to (across) the 8X18 of the casing. In this way, thephysical properties parallel and perpendicular to the direction ofextrusion of the casing may be determined.

A 2-inch section of easing /2-inch wide is clamped between the jaws ofthe Instron Tensile Tester in such a manner that the length of the casinsuspended between the two jaws is 1 inch. The jaws of the InstronTensile Tester are then positioned 1 inch apart and the casing sampl issprayed with distilled Water.

Two minutes after the test sample has been soaked with water, the clampsof the Instron T ensile Tester are moved apart at the rate of 1 inch perminute until the distance between the moving jaws is 1.22 inches. Themovement of the jaws is then stopped.

The stylus trace 15-16 of FIGURE 2 is a reproduction of a typicalstress-strain curve from an Instron Tensile Tester chart obtained with awet casing stretched from 1 inch to 1.22 inches at room temperature. Itwill be noted that no tension is recorded until the jaws have moved1.057 inches apart (point 15). This distance (1.057 inches) is thelength of the casing after it has been wet with water and this distance,minus the original length (1 inch) times 100, is the percent swellingthat tal'es place when the casing is wet out. From FTGURE 2, the percentswelling may be calculated as equal to 1.057 inches minus 1 inch times100 or 5.7.

From the slope of the line 1516 in FIGURE 2, it will be noted that thestrain in inches per pound of stress is 1.48. This value, which isrelated to the reciprocal of Youngs modulus will be referred tothroughout the specification as M (the modulus of the wet casing at roomtemperature) The jaws of the Instron Tensile Tester are next reverse sothat they approach to Within 1 inch, releasing all tension and then thejaws of the Instron Tensile Tester are again moved apart at the rate of1 inch per minute until the casing breaks. The third stress-strain curveso obtained is illustrated by FIGURE 3, from which curve one may measurethe deformation and wet tensile strength.

It will be noted from FlGURE 3 that no tension is recorded until theclamps have moved 1.088 inches apart (point 17). This distance is themeasure of the length of the casing after it has been Wet out, stretched22 percent and then relaxed. This distance minus the original length (1inch) is the change of length due to both swelling and deformation understress and throughout the specification and claims will be referred toas combined swell and deformation.

The percent deformation may be calculated from FIGURES 2 and 3 bysubtracting the length of the sample after swelling (indicated at point15 of FIG- URE 2) from the length of the sample after it has been wetout, stretched 22 percent and relaxed (point 17 of FIGURE 3). Thus, thepercent deformation of the sample illustrated by FIGURES 2 and 3 ispercent deformation equals 1.088 minus 1.057 times 100 or 3.1.

In FIGURE 3, point 13 indicates the sudden breaking point of the casing,the tension dropping suddenly to zero. This point 13 is the measure ofthe tension or applied force at the break point. The casing having thestress-strain curve illustrated in FIGURE 3 snapped under an appliedforce of 0.680 pound. The force required to break the wet sample at roomtemperature under the test conditions described above will be referredto throughout this specification as the wet tensile strength.

Typical casings of the present invention have the following illustrativeproperties when tested on an Instron Tensile Tester as described above.

The change of length due to shrinkage AL amounts to from about 1.0 inchto about 2.0 inches.

The strain in inches per pound or" stress 6 is from about 1.0 to about10.0 inch-pounds. This test is carried out at 99 C.

The hot tensile strength is from about 0.3 pound to about 1.2 pounds.

The shrink tension is from about 0.3 to about 1.0 pound.

The percent recovery amounts to from about to about 150.

The combined swell and deformation which is most important to thestuffing and linking properties of the casing is from about 6% to about14%.

The modulus at room temperature M (measured either perpendicular orparallel to the direction of extrusion) is from about 0.3 to about 1.5inch-pounds.

The wet tensile strength (measured either perpendicular or parallel tothe direction of extrusion) is from about 0.7 pound to 1.5 pounds. Thistest is conducted at room temperature.

The burst strength is at least about 10 to 28 pounds per square inch.Burst strength is the air pressure in pounds per square inch required toburst dry extruded collagen casings which have a wall thickness of 1mil. The values of burst strength expressed in this specification aredetermined in a Perkins Mullen Tester (Model C). Liquid under uniformlyincreasing pressure expands against a distensible rubber diaphragm and,simultaneously, into a Bourdon pressure gauge. The material to be testedis clamped securely to a metal plate through which the diaphragm is freeto expand through a circular opening against one square inch of itssurface. As the sample distorts under pressure, the diaphragm assumesthe exact contour of the material, uniformly distributes the pressureover the entire test area, and protrudes into any imperfection or Weaksection to burst or rupture it at that point. When the pressure drops atthe moment of rupture, a maximum hand on the gauge remains stationary Vlinker.

. 7 to indicate the exact pressure at the time the burst occurred.

The casing of this Example I is about 1 mil in thickness and is suitablefor casings for sausages of the Wiener or frankfurter type. It has thefollowing physical properties:

Example II An extruded collagen casing is prepared exactly as describedin Example 1 above except that the collagen mass extruded contains 4percent by weight hide solids instead of 3.2 percent hide solids. Afterproper humidification at 70% relatively humidity and room temperaturefor 2 days this casing is shirred on conventional shirring equipment,stuffed with pork sausage and linked on the Famco This sausage cookedsatisfactorily without rupture of the casin This casing also performedsatisfactorily when stuffed with Wiener emulsion and linked with the Tylinker. After smoking, the Wiener has a good appearance and cookssatisfactorily. The casing is as tender as a natural casing and has thefollowing physical properties:

Example III A casing is prepared exactly as described in Example I aboveexcept that the collagen mass is passed only once through theManton-Gaulin homogenizer. The concentration of collagen in the massextruded is 4 percent by Weight. The casing so prepared, when properlyhumidified, is suitable for use as a casing and may be used for eitherpork sausages or Wieners. It does not break on linking or wrinkle duringsmoking. The casing of this example has the following physicalproperties:

Burst Strength, pounds 17. 9 Shrink Tension Results:

AT. 1. 58 Initial Modulus, e 3. 50 Percent Recovery 108 Shrink Tension0.519 Hot Tensile Strength 0. 802

Parallel Perpendicular Wet Modulus Results:

Percent Swell 2. 96 9. 70 Percent Deformation 6. 4. 66 Combined Swelland Deforma ion. 9. 11 14. 36 Modulus, 0. 350 1. 49 Wet Tensile Strength1.35 0. 94

. 8 Example IV An extruded collagen casing is prepared exactly asdescribed in Example I above except that the collagen mass extrudedcontains 4 percent by weight hide solids instead of 3.2 percent hidesolids. The plasticizing bath contains 3.7 percent glycerol and 0.2percent mannose. The casing is inflated and dried at room temperatureand then heated for 20 hours at C.

The casing so obtained is stufied and passes the Ty linking test. Thistest is performed by wrapping Ty linker string around the stuffed casingthree times and pulling the string up tight with a quick jerk. Casingswhich pass this test without cutting or breaking may be processed on aTy linking machine.

The casing of this example has the following physical properties:

Burst Strength, pounds 18 Shrink Tension Resul AL 1. 05 Initial Modul 1.20 Percent Recovery. 96 Shrink Tension. 0. 84 Hot Tensile Strengt 0. 81

Parallel Perpendieular Wet Modulus Results:

Percent Swell 4. 5 3. 70 Percent Deformation 3. 5 3.60 Combined Swelland Deforln tie 8.0 7. 8O Modulus, M O. 35 0.24 Wet Tensile Strength0.77 0. 89

Example V An extruded collagen casing is prepared exactly as describedin Example IV above except that the plasticizing bath contains 3.7percent glycerine and 0.02 percent mannose. The finished casing passedthe Ty linking test and has the following physical properties:

Burst Strength, pounds Shrink Tension Results:

Initial Modulus, e Percent Recovery Shrink Tension Hot Tensile StrengthParallel Perpendicular Wet Modulus Results:

Percent Swell Percent Deformatio Combined Swell and Deformation.Modulus, M Wet Tensile Strengt SSSSS Example V1 Burst Strength, pounds16 Shrink Tension Results:

AT, 1. 20 Initial Modulus, e 2, 48 Percent Recovery- 109 Shrink Tension0.48 Hot Tensile Strength 0. 72

Parallel Perpendicular Wet Modulus Results:

Percent Swell 2.00 3. 50 Percent Deformation 3. 50 4. 40 Combined Swelland Deformation-. 5. 5O 7. 90 Modulus, M 0.33 0.36 Wet Ten leStrength.-- 0.91 0.91

Example VH Burst Strength, pounds Shrink Tension Results:

Initial Modulus, e Percent Recovery Shrink Tension Hot TensileStrength...

Parallel Pei-pendicular Wet Modulus Results:

Percent Swell Percent Deiormation. Combined Swell and DeformationModulus, Wet Tensile Strength The invention described and illustratedhereinbeiore and secured by these Letters Patent is defined in thefollowing patent claims.

What is claimed is:

1. An edible sugar-treated and heat-cured translucent casing of coheredcollagen fibrils derived from unlimed hides characterized by a combinedswell and deformation of no less than 5.5% and no more than l4.4%.

2. The casing of claim 1 in a Shirred condition.

3. The casing of claim 1 wherein the wet tensile strength is no lessthan 0.68 and no more than 1.5.

4. The casing of claim 1 wherein the shrink tension is no less than 0.29and no more than 1.0.

5. An edible sugaJ-treated and heat-cured casing comprising anon-collagenous fibrous material encapsulated in a matrix of unlimedhide collagen fibrils cohered to form a translucent hyaloid structureand characterized by a combined swell and deformation of no less than5.5% and no more than 14.4%.

6. The casing of clmrn 5 in a sbirred condition.

7. The casing of claim 5 wherein the wet tensile strength is no lessthan 6.68 and no more than 1.5.

8. The casing of claim 5 wherein the shrink tension is no less than 0.29and no more than 1.0.

9. The edible sausage comprising a sugar-treated and heat-cured collagencasing of cohered unlirned hide collagen fibrils, said casing having acombined swell and deformation of no less than 5.5% and no more than14.4% and containing a meat product whereby the sausage will retain asmooth symmetrical appearance after smoking.

10. An edible sausage comprising a translucent sugarireated andheat-cured collagen casing having a combined swell and deformation of noless than 5.5% and no more than 144%, said casing being composed ofnon-collagenous fibrous material encapsulated in a matrix of unlimedhide collagen fibrils cohered to form a hyaloid structure, andcontaining a smoked beer" product.

11. A smoked sausage comprising a sugar-cured collagen tube of coheredunlimed hide collagen fibrils filled with a Wiener emulsion, the tubehaving a combined swell and deformation of no less than 5.5% and no morethan 14.4% and adhering to said emulsion and edible therewith.

12. Smoked sausages comprising a continuous sugartreated and heat-curedcasing comprising cohered unlirned hide collagen fibrils, portions ofsaid casing con taining Wiener emulsion and tied links in the casingforming a plurality of linked individual Wiener sausages, said casingbeing characterized by a combined swell and deformation of no less than5.5% and no more than 14.4%.

References tilted in the file of this patent UNITED STATES PATENTS2,257,222 Bergmann Sept. 30, 1941 2,346,417 Cornwell et a1. Apr. 11,1944 2,704,259 Lamb Mar. 15, 1955 2,747,228 Eraun et al May 29, 19562,748,774 Novak June 5, 1956 2,852,812 Braun Sept. 23, 1958 2,866,710Dowd et a1. Dec. 30, 1958

1. AN EDIBLE SUGAR-TREATED AND HEAT-CURED TRANSLUCENT CASING OF COHEREDCOLLAGEN FIBRILS DERIVED FROM UNLIMED HIDES CHARACTERIZED BY A COMBINEDSWELL AND DEFORMATION OF NO LESS THAN 5.5% AND NO MORE THAN 14.4%.